Test tube agitation devices are known in the prior art and include a powered support on which the test tube to be agitated is set. To activate the agitation movement, either a manually activated switch or a microswitch arranged beneath the support and to be started by pressure of the test tube on the support is used. In the first case there is the disadvantage of having to use two hands, one to hold the test tube and the other to operate the switch, and the disadvantage of forgetting the started agitator after use. In the second case, one is required to manually exert a certain pressure on the test tube to start it with the possible risk of breaking test tubes of thinner glass and in any case with the need of a small physical effort that might in time bring a not negligible fatigue of the hand, especially in large analysis-laboratories where the same analyst performs a large number of agitations each day.